Only sceptics would have cheered the recent climate-change summit. If the lack of consensus was any guide, the prospect of attaining it is dim at a United Nations conference in Paris in a year aimed at sealing a new, legally binding treaty to reduce global-warming gas emissions. The presence of national leaders was supposed to give negotiations momentum. But the president of China and prime minister of India didn't show up, leaving a third of the world's population to be represented at a lower level; nor did the chancellor of Germany. Those who did offered little to overcome obstacles to wider agreement between developing and developed nations. Without breakthroughs soon, a rerun of the acrimonious and hugely disappointing Copenhagen summit of 2009 seems more likely than not. That said, UN Secretary General Ban Ki-moon's call to set the world on a new course did not go entirely unanswered. The European Union, for example, said that by 2030 member nations would cut greenhouse gases to 40 per cent below 1990 levels. But most attention fell on China, following a report by leading research institutes that its carbon emissions have eclipsed those of the United States and EU combined. China pledged cuts to carbon intensity at the high end of its targeted range by 2020 compared with 2005 - 45 per cent per unit of gross domestic product. Rapid economic growth means carbon output will continue to rise, but the pledge reflects growing public pressure to tackle serious air pollution and raises hopes among environmentalists that China will become more amenable to a carbon cap in future talks. Vice-Premier Zhang Gaoli told the meeting China was committed to cutting greenhouse emissions and would make even greater efforts. While officials said they did not know when China would stop increasing carbon emissions, environmentalists hailed the 45 per cent pledge. Li Junfeng, director general of the National Centre for Climate Change Strategy, said his centre had prepared policy options for Beijing for reducing the use of coal that involved changes to industry. So long as China pursues high growth to move beyond being an industrial economy, it will rely on burning coal. Expansion of regional emissions cap-and-trade plans, investment in renewable energy and technology transfer from the developed world offer the best hope of putting a date on when emissions will turn downwards.